Using a Minimum Data Set, we studied how the mental and physical conditions of elderly people with dementia changed during two years of institutionalization. Fifty-five patients with dementia of Alzheimer's type (DAT) and 25 with vascular dementia (VD) admitted to the dementia ward in Kyoto Higashiyama Geriatric Hospital were investigated. We assessed them at the time of their institutionalization, and every three months for two years. On institutionalization, a difference between DAT and VD was noted in the group in which more than 10 areas of Resident Assessment Protocols (RAPs) were triggered. The areas of delirium, communication, behavioral problem, activities, activities of daily living, dehydration/fluid maintenance, and psychotropic drugs were evenly triggered in both dementia groups. In the DAT group, however, mood state and dental care were also highly triggered while urinary incontinence, falls and nutritional status were highly triggered in the VD group. Three months later, marked improvements were observed in all of the above areas. However, RAPs areas gradually increased subsequently, and there was marked difference in the areas and their course of progression between the dementia groups. In the DAT group, the trigger rate of the areas of communication, activities of daily living, urinary incontinence, dental care, nutritional status and falls gradually increased after 6 months of evaluation. However, the trigger rate in only three areas, such as communication, visual function and urinary incontinence, become higher, but their patterns of increase were irregular. Mental and physical conditions of the patients with dementia were different in each dementia subtype on institutionalization, but these conditions improved soon after. However, the conditions were gradually became worse, and the pattern was different in each dementia group: DAT showed a slow and steady decline, but VD showed irregular progression and differed among individuals.